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The scientific study of the origin, history, and structure of the earth.

The earth's landscape is always changing, but the changes happen so slowly that they are difficult to see. Forces such as heat and pressure change the landscape through weathering and erosion. It can take thousands of years for rocks to change shape through erosion, and millions for one rock type to transform into another.

Find out more about this topic by clicking on the buttons on this page. You can watch our broadcast show, Science Trek: The Web Show, and our video shorts in our player. Facts will tell you more about the topic. Links will expand your learning beyond our site. Glossary gives you a list of specialized words. Resources offer reading suggestions. Games give you a chance to play. Top Ten are answers to ten of our favorite questions asked by students. Teachers provides materials for educators. Archive takes you to video files from past shows not on our current player. Contact us by clicking on the link in the masthead to email us questions or comments. Click for the current season’s schedule of programs, learn more about the scientists on this show and be sure to check out my blog.